(transitive) To make damp or moist; to make slightly wet.
(transitive) To depress; to check; to make dull; to lessen.
The CenturyIn a way that considerably dampened our enthusiasm.
2007 October 16, Jane E. Brody, “Despite Strides, Listeria Needs Vigilanceâ€, The New York Times,Pregnant women are 20 times as likely as other healthy young women to contract listeriosis, probably because in pregnancy the immune system is dampened to prevent rejection of the fetus.